Inter- and intra-host sequence diversity reveal the emergence of viral variants during an overwintering epidemic caused by dengue virus serotype 2 in southern Taiwan

by Hui-Ying Ko, Yao-Tsun Li, Day-Yu Chao, Yun-Cheng Chang, Zheng-Rong T. Li, Melody Wang, Chuan-Liang Kao, Tzai-Hung Wen, Pei-Yun Shu, Gwong-Jen J. Chang, Chwan-Chuen King Purifying selection during dengue viral infection has been suggested as the driving force of viral evolution and the higher complexity of the intra-host quasi-species is thought to offer an adaptive advantage for arboviruses as they cycle between arthropod and vertebrate hosts. However, very few s tudies have been performed to investigate the viral genetic changes within (intra-host) and between (inter-host) humans in a spatio-temporal scale. Viruses of different serotypes from various countries imported to Taiwan cause annual outbreaks. During 2001–2003, two consecutive outbreaks were caus ed by dengue virus serotype 2 (DENV-2) and resulted in a larger-scale epidemic with more severe dengue cases in the following year. Phylogenetic analyses showed that the viruses from both events were similar and related to the 2001 DENV-2 isolate from the Philippines. We comprehensively analyzed vir al sequences from representative dengue patients and identified three consensus genetic variants, group Ia, Ib and II, with different spatio-temporal population dynamics. The phylodynamic analysis suggested group Ib variants, characterized by lower genetic diversity, transmission rate, and intra-hos t variant numbers, might play the role of maintenance variants. The residential locations among the patients infected by grou...
Source: PLoS Neglected Tropical Diseases - Category: Tropical Medicine Authors: Source Type: research